The second half is therefore much more interesting than the first; even so, the whole movie suffers from a lack of narrative momentum and a surfeit of wordless shots of men exchanging deep, meaningful glances.

The densely plotted Generation War sweeps past implausibilities and offers the can’t-put-it-down qualities of a superior airport novel; its last third is affecting. But a bold confrontation with the past? Not so much.

The filmmaking style is practically nonexistent: interviews and static shots of the performers onstage. They are thoughtful and often funny, especially Mat Fraser, a British man whose arms were damaged by Thalidomide, and Julia Atlas Muz, the off-stage partner with whom he often performs.

Directors Aron Gaudet and Gita Pullapilly overload their too-long film with subplots. Yet the actors — including a terrific Aiden Gillen (“Game of Thrones”) as Casper’s no-good father — perform as though unaware that any of this is a cliché.

The cast, so packed with talent that Jean Reno and Cherry Jones barely register, is stuck with stagey dialogue. Juliet Rylance, in the Nina part, has a particularly hard time. But there are good points, including Janney’s obvious pleasure in her part.

It's deeply frustrating to discover that this 2012 movie has precisely the same concerns as the ["The Women"] - appearance and men - with raunchy frankness about sex added and every trace of real wit siphoned out.

The plot, however, comes with twists you can spot as far off as a Himalayan peak. The dialogue is heavily expository, and the actors are not up to the task of breathing life into characters meant to symbolize the Spirit of the Afghan People or the Nature of Evil.

The plot is predictable, as complications line up like jets awaiting takeoff. Even the camera work is predictable: The attractive-girl's-scary-boyfriend-suddenly-pops-up shot; the morning-after, face-in-the-pillow shot.

The director has cited "Inglourious Basterds" as paving the way for his own movie; but for all his boldness, Quentin Tarantino avoided the camps altogether. My Best Enemy shows the camps only briefly, but once it does, it becomes both too much, and not enough. Once you see even a long shot of such a place, the impulse to find humor in much of anything is gone.

Part of the limp-rag ambience is due to Talt, who seems to be channeling Sarah Jessica Parker — which, unsurprisingly, does not work. Mostly it’s due to the script, which fails to meet the major romantic-comedy requirement of being clever about keeping lovers apart. All by itself, “The hero is kind of a drip” doesn’t cut it.

Give director Paul Borghese credit for daring in giving his movie a title that evokes Sergio Leone’s two most famous epics. The trouble with doing that, of course, is that you better be prepared to deliver a movie on the same level.

Big Star’s fans are so passionate that this film may well please some of them, but as for myself, I already knew their music was genius. By the end, I was muttering at every critic and musician and record producer, “Guys, tell me something I don’t know.”